Organization and Description of Business - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Jul. 01, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Subsidiary Or Equity Method Investee [Line Items]
Convertible preferred stock outstanding		0	92,790,094
Initial share reserve		33,656,200
2019 Plan
Subsidiary Or Equity Method Investee [Line Items]
Initial share reserve	15,519,170
Convertible Preferred Stock
Subsidiary Or Equity Method Investee [Line Items]
Convertible preferred stock outstanding		93,039,737	92,790,094	92,656,029	87,797,854
Initial Public Offering
Subsidiary Or Equity Method Investee [Line Items]
Shares issued	17,250,000
Public offering price	$ 20.00
Net proceeds	$ 315.9
Underwriting discounts, commissions and other costs	24.1
Offering expenses	$ 5.0